I have to step in here for just a minute. I have been making performance chips and flashing CPU's for over 6 years now. I use a Dynojet Dyno to do custom tunes. I tune only for GM cars 1985 to 1995. It is easy to buy a "one size fits all chip" and stick it in your car. With these chips the manufacture will not take any chances with volume metric efficiency, power enrichment or timing because of the liability for doing damage to the car. About all you ever get are lower fan settings, a higher redline and maybe a firmer shift with an automatic transmission. There usually isn't very much HP to squeeze out of a car by just changing the chip. If a free flow exhaust and a K&N air filter are added you can tune for a bit more. Just don't expect magic here.